If you have a Medicare Advantage or Medicare prescription drug plan, you may receive an important document each fall called an Annual Notice of Change, or ANOC.
The ANOC explains what your current Medicare plan is changing for the next calendar year — including changes to costs, coverage, and other plan details. For notices arriving in fall 2026, the changes generally take effect January 1, 2027.
Receiving an ANOC does not automatically mean you need to switch plans. But it is worth reviewing carefully before Medicare Open Enrollment because even a plan that worked well this year may have different costs or coverage next year.
What Is a Medicare ANOC?
ANOC stands for Annual Notice of Change.
Medicare says that if you're enrolled in a Medicare plan, your plan sends this notice each fall to explain upcoming changes in coverage, costs, and other plan features that will take effect in January.
This generally applies to people enrolled in plans such as:
Medicare Advantage plans
Medicare Advantage plans that include prescription drug coverage
Stand-alone Medicare Part D prescription drug plans
The ANOC is sent by your current plan, not as an advertisement from a competing insurance company.
If you have only Original Medicare and aren't enrolled in a private Medicare health or drug plan, you generally won't receive this type of ANOC from a plan.
Why Does the ANOC Arrive in September?
The timing is intentional.
Medicare lists September as the time beneficiaries should receive the ANOC. CMS rules generally require plans to ensure current members receive it by September 30.
That gives you time to review next year's changes before Medicare Open Enrollment.
For coverage beginning in 2027, Medicare Open Enrollment runs from October 15 through December 7, 2026. Changes made during this period generally take effect January 1, 2027.
Medicare also encourages beneficiaries to begin comparing their current coverage with 2027 options starting October 1.
What Should You Check in Your ANOC?
Don't look only at whether your monthly premium changed. A plan with the same or a similar premium could still have important differences in what you pay or how your coverage works.
Here are some of the most important areas to review.
Monthly Premium and Other Costs
Check whether your plan premium will increase, decrease, or remain the same.
Also look beyond the premium. Depending on your plan, changes in deductibles, copays, coinsurance, or other out-of-pocket costs could have a bigger effect on your annual spending.
Deductibles, Copays, and Coinsurance
Compare what you currently pay for services or prescriptions with what the plan says you'll pay in 2027.
For a Medicare Advantage plan, pay particular attention to services you use regularly, such as specialist visits, hospital care, outpatient services, or other covered care.
Prescription Drug Coverage
If your plan includes Part D drug coverage, check your medications for the coming year.
A plan's formulary — its list of covered prescription drugs — can change. A medication may also move to a different tier or have different coverage requirements or cost sharing.
Rather than assuming your prescriptions will be covered exactly as they are now, check the plan's 2027 drug information for medications you regularly take.
Pharmacy Changes
Pharmacy arrangements can also affect what you pay for prescriptions.
Check whether your preferred pharmacy remains in the plan's network and whether its cost-sharing status has changed. Some plans may have preferred pharmacies where members pay less than at other network pharmacies.
Doctors and Provider Networks
If you have a Medicare Advantage plan that uses a provider network, don't assume that every doctor, hospital, or other provider you use will have the same network status next year.
The ANOC can alert you to plan changes, but it is also wise to check the plan's current provider directory and, when important, confirm directly with both the provider and the plan.
Benefits and Coverage
Medicare Advantage plans may offer benefits beyond Original Medicare, and those benefits can change from year to year.
Review benefits that matter to you rather than focusing only on advertised extras. Also check for changes in coverage rules, service areas, or other plan provisions that could affect how you receive care.
What Should You Do If Your Plan Is Changing?
First, decide whether the changes actually matter for the care and prescriptions you use.
A practical review can include:
Your regular prescription drugs
Your preferred pharmacies
Doctors, specialists, and hospitals you use
Premiums and other expected costs
Benefits that are important to you
Then compare your current plan's 2027 coverage with other available Medicare options if necessary. Medicare's official Plan Compare tool can help you compare Medicare Advantage and Part D plans available in your area.
You don't need to switch simply because something changed. The goal is to determine whether your current plan still fits your needs.
What Happens If You Do Nothing?
If your plan continues to be offered in your area, you remain eligible, and the plan is renewing your coverage, you generally don't need to re-enroll simply to stay in the same plan.
However, the new year's plan terms apply. That means any applicable changes in costs or benefits described for 2027 generally begin January 1.
This is why ignoring the ANOC can be a mistake even when you intend to stay with the same plan.
A separate situation applies if a plan is leaving Medicare or will no longer be available to you. Medicare uses specific non-renewal notices for those circumstances, and you may need to choose different coverage.
ANOC vs. Evidence of Coverage: What's the Difference?
These two documents serve different purposes.
The Annual Notice of Change focuses on what is changing from the current year to the next year.
The Evidence of Coverage (EOC) provides more detailed information about how your plan works, including what it covers, what you pay, and other plan rules.
A simple way to think about it is:
ANOC = What's changing?
EOC = How does my plan work?
Both are useful documents to keep for reference.
Frequently Asked Questions
Is a Medicare ANOC important?
Yes. It tells you about changes to your current Medicare plan that take effect the following January. Even if you plan to keep your coverage, reviewing it can help prevent surprises.
Does receiving an ANOC mean I need to change Medicare plans?
No. An ANOC is a notice of upcoming changes, not an instruction to switch plans. If your current coverage still meets your needs, you may decide to keep it.
When should I receive my Medicare ANOC for 2027?
Medicare says ANOCs arrive in September, and CMS requirements generally call for current plan members to receive the notice by September 30.
What if I don't receive my ANOC?
Contact your Medicare plan. Medicare specifically advises beneficiaries who don't receive this important document to contact their plan.
When can I change Medicare plans for 2027?
Medicare Open Enrollment runs from October 15 through December 7, 2026. Changes made during this period generally begin January 1, 2027.
Bottom Line
If a Medicare Annual Notice of Change arrives in your mailbox or electronically this September, don't automatically assume you need a new plan — but don't ignore it either.
Check what will change in 2027, especially your premiums and other costs, medications, pharmacies, provider network if applicable, and benefits you actually use.
If your current coverage still works for you, you may not need to make a change. If the changes could significantly affect your care or costs, Medicare Open Enrollment gives you an opportunity to compare your options before December 7.